This invention relates to an asphalt surface for a roadway, or the like, that incorporates integrated edge portions that provide a shield against water and/or plant roots.
A problem encountered with asphalt driveways, roadways, and the like, is the intrusion by water or plant roots along the edge of the asphalt. In winter, water that has found its way under the asphalt at the edges freezes, and freeze-thaw cycles cause shifting and cracking of the asphalt surface. In summer, roots from grass and/or trees, may grow under the edge and cause uplifting and damage to the edges of the asphalt surface. Curbs commonly used along the edges of streets usually do not prevent the problem since it is difficult to maintain a good seal between the curb and asphalt roadway, and eventually water will find its way under the edges of the roadway causing the above-mentioned problems with freezing and possibly also plant roots
The use of the term xe2x80x9casphaltxe2x80x9d as used herein refers to a mixture of a bituminous binder and aggregate as is commonly used for roadway surfacing.
An object of the present invention to provide shielding edges for asphalt surfaces to alleviate the problems associated with water and/or plant root intrusion.
It has been found that the problems caused by water or roots under the edges of an asphalt surface can be alleviated by providing a shielding edge portion that is integral with, and extends below the asphalt surface to prevent the intrusion of water and roots.
The present invention provides a method of forming a shielded asphalt surface on a prepared subgrade, comprising: forming a recess along the outer edge of the subgrade; depositing asphalt into said recess and compacting the deposited asphalt to form an edge portion at substantially the same height as the subgrade; depositing asphalt onto the subgrade, to form a roadway surface, and onto the edge portion; and compacting the deposited asphalt thereby integrating the asphalt that forms the roadway surface with the asphalt that forms the edge portion to provide a monolithic shielded asphalt surface.